Schools across Northern Ireland are set to experience disruption on Wednesday as teachers take part in strike action.
It is the latest walkout to take place in a running dispute over pay.
Teachers at schools took part in a half-day strike in February, while there was a full day of strike action in schools and further education colleges in April.
Separately, school support workers have also taken strike action over pay.
One of the larger unions for teachers, the NASUWT, is calling for a fully funded 12% pay award for 2023/24.
The union said the last 13 years have seen cuts of 38% to teachers’ pay in real terms.
With the continued collapse of the Stormont Assembly and Executive, the union is calling for the UK Government to intervene.
Dr Patrick Roach, NASUWT general secretary, described the pay situation as “simply intolerable”.
“Teachers have not had a pay increase for three years while further education lecturer pay is even worse again,” he said.
“Our members shouldn’t be in the position where they must take industrial action to get the same basic rates of pay as colleagues elsewhere in the UK.
“Teachers and lecturers have seen their pay cut in real terms while their living costs continue to rise on a weekly basis.
“This is a disgrace, and the UK Government needs to address this urgently.”
Justin McCamphill, NASUWT national official Northern Ireland, added: “This is the third teachers’ strike this year, and members resolve has strengthened since April.
“They do not want to hear any more excuses and are demanding that they are paid the same as any other teacher in the UK. A Northern Ireland teacher is not worth less than an English or Scottish teacher.
“The Department of Education and the Department for Economy, along with the employers, must bring forward a substantially improved pay offer if they want to see an end to these disputes.
“In the absence of a (Stormont) executive, the UK Government must ensure that teachers and lecturers in Northern Ireland are paid the same as their counterparts elsewhere in the UK.”
Northern secretary of another teacher’s union INTO, Mark McTaggart, said teachers do not want to strike but have been left with no other option.
“Teachers’ pay has fallen by 25% over the past decade. The effect is already obvious with the continued shortage of teachers due to issues around recruitment and retention,” he said.
“Teachers here are the lowest paid across these islands, with the gap in pay widening over the past three years. If those who control the purse strings truly want children and young people to have access to the best possible education available, they must bring about a fair pay settlement for teachers and school leaders.”